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A. SCHOELLER.

COMBINED AMPERE AND VOLT MEER.

APPLICATION FILED DEc.2. 1913.

1,195,508. Patent-@Aug 22,1916.

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'ALFRED SCHOELLER., 0F.RANKFORT-ON-THEVMAIN, GERMANY.

COLBINED AMPERE-AND VOLT METER.

particularly for measuring current and volt-A age for use in vehicles and other structures subject to continual vibration.

The invention rests upon the consideration that it is of substantial advantage in instruments permanent-ly exposed to vibration to diminish as much 'as possible the number of connecting screws and particularly to avoid small screws which cannot be locked, and further to be as sparing as pos# lsible otterminals for electric connections.

In consequence of the-j arring to which 'motor cars, railway vehicles, andthe like are exposed, both electrical and mechanical connections become loose and then cause dis` turliances, the origin of which is only discovered with great difficulty.

The object of the present invention is to ohtain greater reliability of operation, to-

V`getherl -with increased. cheapness and ae curacy of measurement.

According to the present invention' the permanent magnets, the supporting plate for the series resistance, the terminal springs for the moving coil, the yseries resistance, and the change-overcontacts of the instrument arc arranged one above the otherl with the necessary insulation between them, and all of these parts are fastened upon a base plate by means of a bridge beam and only two screws.

The accompanying drawings illustrate one construction according to the invention.

Figure l showing the instrument from .meter and voltsmcter, except the moving sysli-ni. are fastcni-.il upon a hase plate I1 by 'terminal piece D, and a plate E.

' Specification of Letters Patent. `Itltd Allg. 22, QS.

Application ined December 2, i913,

Serial No. 804,208.

means of only twoscrews A', A2 l).

These parts are a contact spring C, connected with one end of the moving coil, a series resistance 'W for voltage measurements, a These parts are fastened together in a rigid whole with the supporting plate G for the moving system, themagnet M, and a bridge piece B, by means of the two screws A', A2. The two screws A', A2 therefore carry the whole of the internal parts of the instrument.

The separate parts are insulated from one another by intervening layers of mica as far as this is necessary for the connections.'

By means of the contact spring `C the moving system can be connected for voltage measurements in series with the resistance NV, or for current measurements across the snunt' J into the circuit to be measured. This is achieved by the Contact ioints mounted respectively upon the plate L carrying the resistance W, and upon the shunt J. The bridge piece B further carriesvthe scale F. The moving system S .is fastened upon its support G, and hns its spindle turning m the upper and lower plates R. T.` In

`the case illustrated, one terminal'lis the ca.,-

ing t the instrument itself; Thereore'the plate I) on which one end of the resistance IV is fastened is supported without insula tion directly on the base plate H. The other end oi' the resistance Vif" connected to the plate E. The shunt J is insulated from the base plate and therefore from the casing.

Having now particularly describedand ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claiin is:

l. A combined ampere and volt meter comprising a hase, a permanent magnet, a

'series resistance, a plate supporting said series resistance, -a moving coil, a terminal piece for vsaid moving coil and the series resistance, a hridgefpiece, and a pair of screws engaging said bridge-piece and securing said parts to the base, substantially as described.

2. A combined ampere and volt meter v comprising a base, a permanent magnet, a

series resistance coil, a shunt a plate supporting the series r stance coil, moving system, a plate VSYorting the mov'rig system, a terminal piece, a Contact coil;

member, Contact points for said series and shunt coxls, a budge-1Macc, and a pau* of v:screws passing'tl'lrough said bridge-piece,

thefsupporting plates, and the terminal piece,` and securingsuid parts and the permanent magnet to the base, substantially as described.

In testimonjnwhereof I afx my signature in the psence of two witnesses.

A ALFRED SCHOELLER.

W tnesses I FRLEDRICH CARL VVENTZEL, MAX' HEKMANN HPNER. 

